Re: [802.3ae] Clause 52 - receiver bandwidth measurement
Hi Kevin -
Do you understand that during this test, the pattern generator signal runs
at a constant rate of 10.3125? It is only the frequency of the RF source
that is being swept, and the test is measuring the ability of the Rx to
reject it at high frequencies.
Something that I think requires clarification is that the average optical
power of the RF source must be great enough to prevent the RF swing from
driving it below threshold.
Tom
----- Original Message -----
From: "Kevin Demsky" <kdemsky@us.ibm.com>
To: <stds-802-3-hssg@ieee.org>
Sent: Friday, November 16, 2001 6:20 PM
Subject: [802.3ae] Clause 52 - receiver bandwidth measurement
>
> Dear 802.3ae,
>
> In draft 3.2, Table 52.9, page 438, titled "10GBASE-S" receive
> characteristics, it lists Receive electrical 3 dB upper cutoff frequency
> (max) = 12.3 Ghz. I can measure this parameter easily when there is no
> clock and data recovery. Does anyone have an idea how to measure this
> parameter given that most of these transceivers have clock and data
> recovery and will not run much above or below 10.3125 Gb/s?
>
> The same goes for Table 52.14, page 440, titled "10GBASE-L receive
> characteristics".
>
> This spec should be required, as laser relaxation oscillation in a direct
> modulated laser and could have 100% overshoot for instance with the
> frequency of oscillation > 12 Ghz. You want the receiver to act as a
> filter and this has to be normative. Are you implying we should just
> guarantee this by design even though we can not test it at the module
> level?
>
> Kevin Demsky
> Integration Team Lead
> IBM Corp.
> 3605 Hwy 52 N
> Dept. QXS Bldg. 040-2
> Rochester, MN 55901
>
> E-mail: kdemsky@us.ibm.com
>
> Phone: 507-253-5799
> Fax: 507-253-1438
>
>